/*
 * Copyright (c) 2001-2008 Caucho Technology, Inc.  All rights reserved.
 *
 * The Apache Software License, Version 1.1
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:
 *       "This product includes software developed by the
 *        Caucho Technology (http://www.caucho.com/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "Burlap", "Resin", and "Caucho" must not be used to
 *    endorse or promote products derived from this software without prior
 *    written permission. For written permission, please contact
 *    info@caucho.com.
 *
 * 5. Products derived from this software may not be called "Resin"
 *    nor may "Resin" appear in their names without prior written
 *    permission of Caucho Technology.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL CAUCHO TECHNOLOGY OR ITS CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
 * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * @author Scott Ferguson
 */

package com.caucho.hessian.io;

import java.io.IOException;
import java.lang.ref.SoftReference;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.WeakHashMap;
import java.util.logging.Level;
import java.util.logging.Logger;

import sun.misc.Unsafe;

import com.caucho.hessian.HessianUnshared;

/**
 * Serializing an object for known object types.
 */
public class UnsafeSerializer extends AbstractSerializer {
	private static final Logger log = Logger.getLogger(UnsafeSerializer.class.getName());

	private static boolean _isEnabled;
	private static final Unsafe _unsafe;

	private static final WeakHashMap<Class<?>, SoftReference<UnsafeSerializer>> _serializerMap = new WeakHashMap<Class<?>, SoftReference<UnsafeSerializer>>();

	private Field[] _fields;
	private FieldSerializer[] _fieldSerializers;

	public static boolean isEnabled() {
		return _isEnabled;
	}

	public UnsafeSerializer(Class<?> cl) {
		introspect(cl);
	}

	public static UnsafeSerializer create(Class<?> cl) {
		synchronized (_serializerMap) {
			SoftReference<UnsafeSerializer> baseRef = _serializerMap.get(cl);

			UnsafeSerializer base = baseRef != null ? baseRef.get() : null;

			if (base == null) {
				if (cl.isAnnotationPresent(HessianUnshared.class))
					base = new UnsafeUnsharedSerializer(cl);
				else
					base = new UnsafeSerializer(cl);

				baseRef = new SoftReference<UnsafeSerializer>(base);
				_serializerMap.put(cl, baseRef);
			}

			return base;
		}
	}

	protected void introspect(Class<?> cl) {
		ArrayList<Field> primitiveFields = new ArrayList<Field>();
		ArrayList<Field> compoundFields = new ArrayList<Field>();

		for (; cl != null; cl = cl.getSuperclass()) {
			Field[] fields = cl.getDeclaredFields();

			for (int i = 0; i < fields.length; i++) {
				Field field = fields[i];

				if (Modifier.isTransient(field.getModifiers())
						|| Modifier.isStatic(field.getModifiers())) {
					continue;
				}

				// XXX: could parameterize the handler to only deal with public
				field.setAccessible(true);

				if (field.getType().isPrimitive()
						|| (field.getType().getName().startsWith("java.lang.")
								&& !field.getType().equals(Object.class))) {
					primitiveFields.add(field);
				} else {
					compoundFields.add(field);
				}
			}
		}

		ArrayList<Field> fields = new ArrayList<Field>();
		fields.addAll(primitiveFields);
		fields.addAll(compoundFields);

		_fields = new Field[fields.size()];
		fields.toArray(_fields);

		_fieldSerializers = new FieldSerializer[_fields.length];

		for (int i = 0; i < _fields.length; i++) {
			_fieldSerializers[i] = getFieldSerializer(_fields[i]);
		}
	}

	@Override
	public void writeObject(Object obj, AbstractHessianOutput out) throws IOException {
		if (out.addRef(obj)) {
			return;
		}

		Class<?> cl = obj.getClass();

		int ref = out.writeObjectBegin(cl.getName());

		if (ref >= 0) {
			writeInstance(obj, out);
		} else if (ref == -1) {
			writeDefinition20(out);
			out.writeObjectBegin(cl.getName());
			writeInstance(obj, out);
		} else {
			writeObject10(obj, out);
		}
	}

	protected void writeObject10(Object obj, AbstractHessianOutput out)
			throws IOException {
		for (int i = 0; i < _fields.length; i++) {
			Field field = _fields[i];

			out.writeString(field.getName());

			_fieldSerializers[i].serialize(out, obj);
		}

		out.writeMapEnd();
	}

	private void writeDefinition20(AbstractHessianOutput out) throws IOException {
		out.writeClassFieldLength(_fields.length);

		for (int i = 0; i < _fields.length; i++) {
			Field field = _fields[i];

			out.writeString(field.getName());
		}
	}

	final public void writeInstance(Object obj, AbstractHessianOutput out)
			throws IOException {
		try {
			FieldSerializer[] fieldSerializers = _fieldSerializers;
			int length = fieldSerializers.length;

			for (int i = 0; i < length; i++) {
				fieldSerializers[i].serialize(out, obj);
			}
		} catch (RuntimeException e) {
			throw new RuntimeException(e.getMessage() + "\n class: "
					+ obj.getClass().getName() + " (object=" + obj + ")", e);
		} catch (IOException e) {
			throw new IOExceptionWrapper(e.getMessage() + "\n class: "
					+ obj.getClass().getName() + " (object=" + obj + ")", e);
		}
	}

	private static FieldSerializer getFieldSerializer(Field field) {
		Class<?> type = field.getType();

		if (boolean.class.equals(type)) {
			return new BooleanFieldSerializer(field);
		} else if (byte.class.equals(type)) {
			return new ByteFieldSerializer(field);
		} else if (char.class.equals(type)) {
			return new CharFieldSerializer(field);
		} else if (short.class.equals(type)) {
			return new ShortFieldSerializer(field);
		} else if (int.class.equals(type)) {
			return new IntFieldSerializer(field);
		} else if (long.class.equals(type)) {
			return new LongFieldSerializer(field);
		} else if (double.class.equals(type)) {
			return new DoubleFieldSerializer(field);
		} else if (float.class.equals(type)) {
			return new FloatFieldSerializer(field);
		} else if (String.class.equals(type)) {
			return new StringFieldSerializer(field);
		} else if (java.util.Date.class.equals(type) || java.sql.Date.class.equals(type)
				|| java.sql.Timestamp.class.equals(type)
				|| java.sql.Time.class.equals(type)) {
			return new DateFieldSerializer(field);
		} else
			return new ObjectFieldSerializer(field);
	}

	abstract static class FieldSerializer {
		abstract void serialize(AbstractHessianOutput out, Object obj) throws IOException;
	}

	final static class ObjectFieldSerializer extends FieldSerializer {
		private final Field _field;
		private final long _offset;

		ObjectFieldSerializer(Field field) {
			_field = field;
			_offset = _unsafe.objectFieldOffset(field);

			if (_offset == Unsafe.INVALID_FIELD_OFFSET)
				throw new IllegalStateException();
		}

		@Override
		final void serialize(AbstractHessianOutput out, Object obj) throws IOException {
			try {
				Object value = _unsafe.getObject(obj, _offset);

				out.writeObject(value);
			} catch (RuntimeException e) {
				throw new RuntimeException(e.getMessage() + "\n field: "
						+ _field.getDeclaringClass().getName() + '.' + _field.getName(),
						e);
			} catch (IOException e) {
				throw new IOExceptionWrapper(e.getMessage() + "\n field: "
						+ _field.getDeclaringClass().getName() + '.' + _field.getName(),
						e);
			}
		}
	}

	final static class BooleanFieldSerializer extends FieldSerializer {
		private final Field _field;
		private final long _offset;

		BooleanFieldSerializer(Field field) {
			_field = field;
			_offset = _unsafe.objectFieldOffset(field);

			if (_offset == Unsafe.INVALID_FIELD_OFFSET)
				throw new IllegalStateException();
		}

		void serialize(AbstractHessianOutput out, Object obj) throws IOException {
			boolean value = _unsafe.getBoolean(obj, _offset);

			out.writeBoolean(value);
		}
	}

	final static class ByteFieldSerializer extends FieldSerializer {
		private final Field _field;
		private final long _offset;

		ByteFieldSerializer(Field field) {
			_field = field;
			_offset = _unsafe.objectFieldOffset(field);

			if (_offset == Unsafe.INVALID_FIELD_OFFSET)
				throw new IllegalStateException();
		}

		final void serialize(AbstractHessianOutput out, Object obj) throws IOException {
			int value = _unsafe.getByte(obj, _offset);

			out.writeInt(value);
		}
	}

	final static class CharFieldSerializer extends FieldSerializer {
		private final Field _field;
		private final long _offset;

		CharFieldSerializer(Field field) {
			_field = field;
			_offset = _unsafe.objectFieldOffset(field);

			if (_offset == Unsafe.INVALID_FIELD_OFFSET)
				throw new IllegalStateException();
		}

		final void serialize(AbstractHessianOutput out, Object obj) throws IOException {
			char value = _unsafe.getChar(obj, _offset);

			out.writeString(String.valueOf(value));
		}
	}

	final static class ShortFieldSerializer extends FieldSerializer {
		private final Field _field;
		private final long _offset;

		ShortFieldSerializer(Field field) {
			_field = field;
			_offset = _unsafe.objectFieldOffset(field);

			if (_offset == Unsafe.INVALID_FIELD_OFFSET)
				throw new IllegalStateException();
		}

		final void serialize(AbstractHessianOutput out, Object obj) throws IOException {
			int value = _unsafe.getShort(obj, _offset);

			out.writeInt(value);
		}
	}

	final static class IntFieldSerializer extends FieldSerializer {
		private final Field _field;
		private final long _offset;

		IntFieldSerializer(Field field) {
			_field = field;
			_offset = _unsafe.objectFieldOffset(field);

			if (_offset == Unsafe.INVALID_FIELD_OFFSET)
				throw new IllegalStateException();
		}

		final void serialize(AbstractHessianOutput out, Object obj) throws IOException {
			int value = _unsafe.getInt(obj, _offset);

			out.writeInt(value);
		}
	}

	final static class LongFieldSerializer extends FieldSerializer {
		private final Field _field;
		private final long _offset;

		LongFieldSerializer(Field field) {
			_field = field;
			_offset = _unsafe.objectFieldOffset(field);

			if (_offset == Unsafe.INVALID_FIELD_OFFSET)
				throw new IllegalStateException();
		}

		final void serialize(AbstractHessianOutput out, Object obj) throws IOException {
			long value = _unsafe.getLong(obj, _offset);

			out.writeLong(value);
		}
	}

	final static class FloatFieldSerializer extends FieldSerializer {
		private final Field _field;
		private final long _offset;

		FloatFieldSerializer(Field field) {
			_field = field;
			_offset = _unsafe.objectFieldOffset(field);

			if (_offset == Unsafe.INVALID_FIELD_OFFSET)
				throw new IllegalStateException();
		}

		final void serialize(AbstractHessianOutput out, Object obj) throws IOException {
			double value = _unsafe.getFloat(obj, _offset);

			out.writeDouble(value);
		}
	}

	final static class DoubleFieldSerializer extends FieldSerializer {
		private final Field _field;
		private final long _offset;

		DoubleFieldSerializer(Field field) {
			_field = field;
			_offset = _unsafe.objectFieldOffset(field);

			if (_offset == Unsafe.INVALID_FIELD_OFFSET)
				throw new IllegalStateException();
		}

		final void serialize(AbstractHessianOutput out, Object obj) throws IOException {
			double value = _unsafe.getDouble(obj, _offset);

			out.writeDouble(value);
		}
	}

	final static class StringFieldSerializer extends FieldSerializer {
		private final Field _field;
		private final long _offset;

		StringFieldSerializer(Field field) {
			_field = field;
			_offset = _unsafe.objectFieldOffset(field);

			if (_offset == Unsafe.INVALID_FIELD_OFFSET)
				throw new IllegalStateException();
		}

		@Override
		final void serialize(AbstractHessianOutput out, Object obj) throws IOException {
			String value = (String) _unsafe.getObject(obj, _offset);

			out.writeString(value);
		}
	}

	final static class DateFieldSerializer extends FieldSerializer {
		private final Field _field;
		private final long _offset;

		DateFieldSerializer(Field field) {
			_field = field;
			_offset = _unsafe.objectFieldOffset(field);

			if (_offset == Unsafe.INVALID_FIELD_OFFSET)
				throw new IllegalStateException();
		}

		@Override
		void serialize(AbstractHessianOutput out, Object obj) throws IOException {
			java.util.Date value = (java.util.Date) _unsafe.getObject(obj, _offset);

			if (value == null)
				out.writeNull();
			else
				out.writeUTCDate(value.getTime());
		}
	}

	static {
		boolean isEnabled = false;
		Unsafe unsafe = null;

		try {
			Class<?> unsafeClass = Class.forName("sun.misc.Unsafe");
			Field theUnsafe = null;
			for (Field field : unsafeClass.getDeclaredFields()) {
				if (field.getName().equals("theUnsafe"))
					theUnsafe = field;
			}

			if (theUnsafe != null) {
				theUnsafe.setAccessible(true);
				unsafe = (Unsafe) theUnsafe.get(null);
			}

			isEnabled = unsafe != null;

			String unsafeProp = System.getProperty("com.caucho.hessian.unsafe");

			if ("false".equals(unsafeProp))
				isEnabled = false;
		} catch (Throwable e) {
			log.log(Level.ALL, e.toString(), e);
		}

		_unsafe = unsafe;
		_isEnabled = isEnabled;
	}
}
